Telephone-exchange system



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J. W. GOODERHAM TELEPHONE EXCHANGE SYSTEM Filed July 14, 1923 5Sheets-Sheet 1 Aug. 2s, 1925. 1,551,023 J. W. GOODERHAM TELEPHONEEXCHANGE SYSTEM Filed July 14. 1923 3 Sheets-Sheet 2 QT ai r.,l.W.'GOODERHAM TELEPHONE EXCHANGE SYSTEM Filed July 14, 1923 3Sheets-Sheet 3 Patented Aug. 25, 1925'.

UNITED STATES PATENT OFFICE.

SOHN W. GOODERI-IAIVI, 0F YONKERS, NEWT YORK, ASSIGNOR TO WESTERNELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEWYORK.

TELEPHONE-EXCHANGE SYSTEM.

Application led July 14, `1923.

To all whom it may concern:

Be it known that I, JOHN W. GooDnRHAM, a citizen of the United States ofVJAmerica, residing at Yonkers, in the vcounty of Westchester, State ofNew York, have invented .certain new and useful Improvements inrTelephone-EXchange Systems, of which the following is a full, clear,concise, and exact description.

This invention relates to telephone exchange systems and particularly toan arrangement for making observations on the service affordedsubscribers lines in the establishment of calls.

In exchange syste-ms where machine switching apparatus is employed atthe central offices for setting .up connections, it is desirable to takeobservations, from time vto time, to ascertain the manner in which `theapparatus is functioning and to determine the quality of service beinggiven the subscribers. Such information is no-t only of interest to thetelephone company in showing the performance of the automatic switchingequipment, but also serves to definitely `ascertain whether complaints.entered by the subscribers against the quality o-f the service are dueto failures in the apparatus or because of an improper usage by thesubscriber of his telephone instrument, or for any other reason.

In order that this information may be readily and conveniently obtained,a special desk is provided in the central ,office and equipped withapparatus and `circuits for taking all the required .observations onsubscribers lines. The observing `operator presiding over the desk mayinspect the koperation of all switching mechanism involved in theextension of any particular subscribers line responsive to theorigination of a call thereon. The observing equipment is arranged to beassociable with any suitable variable number of lines at a time and when,thus allotted it serves to enable observations .on any calling line insuch group. To avoid mistakes, which might arise by interference in theassociation of the equipment with lines calling simultaneously, thearrangement is such that only one line o-f the group can be connected tosaidyequipment ,at a time. When all notations have been taken Serial N0.651,456.

again be connected to some other line in the group.

The present invention is an improvement on the service observing systemdisclosed in my Patent No. 1,504,230 issued to J. W. Gooderham Aug. l2,1924, and more particularly to a sensitive means for receiving thepulses dialled by subscribers whose lines are under observation withoutmaterially changing their efficacy in controlling the recording ofdesired line designations on the registers of central office senders. Afurther feature 4of the invention relates to the provision of means forpreventing `false message register signals during the return to norma-l`of subscribers line switches The object of the invention is thereforeto provide a service `observing equipment for use in automatic telephonesystems, which will lbe accurate in operations and which will operatewithout decreasing the e'ciency of lines with which it is associated.

Referring to the drawing, forming a part of this application Figs. l, 2and 3 when arranged with Fig. 3 below Fig. l and Fig. 2 to the left ofFig. 3, illustrate a, portion of an automatic tele-phone exchange towhich .the circuits and apparatus embodying the principles of thepresent invention are adapted.

Fig. 1 shows, in the upper portion thereof, a subscribers line incomingto the central office fromi whence it extends through the distributingframes to an individual line switch. There is also diagrammaticallyillustrated a trunk leading from the line switch to a first or districtselector, a register sender for controlling selections and a trunkoutgoing from the district selector. In the lower part of this figure asimilar showin-g is given of a subscribers line incoming to the centraloiiice, with t-he exception that in this case line finder switches areused instead of individual line switches for extending calling lines tothe district switches. In both modifications of the switching appara`tus, as shown in Fig. l, there is further illustrated an arrangementwhereby 'connections may be made with subscribers lines for observationpurposes by means of plugs and CII jacks, the plug circuits beingattachable to the line conductors at the distributing frames.

Fig. 2 shows an observing operators position at which there is locatedthe necessary devices for taking observations of the service on callinglines.

In the space set off by the broken lines in the upper right hand cornerof Fig. 3 there are shown the several elements individual to one of theconnecting circuits leading from the jacks shown in Fig. 1 to theobserving operators position. In the small rectangle to the left thereofare shown a few of the corresponding elements individual to a second oneof these connecting circuits. In the remaining portion of the figure,the circuits and relays common to all connecting circuits areillustrated.

Moreover, in addition to being applicable to the two classes of systemsabove mentioned, both of which involve central oliice controlled powerdriven switches, the observing apparatus is also applicable to systemsof the step-by-step character. Although the invention is applicable toother types of systems the present disclosure shows its adaptation to afull mechanical system.

Before describing the features of the operation of the observingapparatus shown in Figs. 2 and 3, an explanation will iirst be given ofthe machine switching mechanism serving the subscribers lines on whichthe service observations are to be made. As

F mentioned above, either individual line switches, such as line switch128, or line linders, such as the iinder 132, may be employed forextending the calling subscribers line through to a district selectorswitch. The district selector 130, shown in connection with asubscribers line served by an individual line switch and the similardistrict selector switch 134 shown in connection with lines served byline finders, may be of the power' driven type in which the selection ofbrushes and the movement thereof into engagement with the desiredoutgoing circuits are accomplished by means of applying a constantlydriven element to the movable member of the switch. The struct-ure andoperation of switches of this general character are shown and describedin detail in the patent to E. B. Craft and J. N. Reynolds No. 1,123,696,issued January 5, 1915. The selective movements of the district switchesand also of succeeding switches in the establishment of the connectionare controlled by means of the revertive impulse register sendersdiagrammatically shown at 131 and 135. rThese senders are of the usualtype used for controlling power driven switches and receive the recordfrom the calling subscribers dial which later serves to govern thedirective movement of the switches. A register sender of the charactersuitable for use in controlling the switches illustrated in the presentsystem is described in detail in a Patent No. 1,395,977, issued to F. A.Stearn and F. J. Scudder, November 1, 1921.

The subscribers line A, which is one of a plurality of lines terminatingin the multiple contacts ofthe line finder 132 on entering the centraloiiice, is lirst directed to the main distributing frame MDF. From hereit leads to the terminal racks of the intermediate distributing frameIDF. Between the main and intermediate frames the subscribers line isdirected through the heat coils 126 which act as a protection againstheavy currents. At the intermediate distributing frame, the line isconnected and distributed to the desired terminals in the bank of theline iinder switch. Vhen it is desired to make observations on thesubscribers line A, a shoe 127 is attached to the line side of theintermediate distributing frame. This shoe is the terminating end of apair of cord circuits 156-157 and la7- 148. These connecting cords attheir other ends terminate, respectively, in the plugs 124 and 123. Tocomplete the association of the line A with the observing position, theplugs 123 and 124: are inserted, respectively, in the jacks of 120 and121 provided at some convenient location in the vicinity of thedistributing frame. From the jacks 120 and 121 the connecting circuit,comprising conductors 102, 103, 106 and 107, leads to the individualapparatus shown in the upper right hand corner of Fig. 3. In this mannerthe line A is connected through to the operators position and theindividual apparatus is now allotted for the sole use of this particularline. In like manner any desired number of other lines similar to line Amay be extended to the corresponding individual mechanisms at theobserving operators position by mea-ns of other plug and jackconnectors. For eX- ainple, a group of forty lines served by the linefinder switches may be connected to the observing position at a timewhereby the observing operator may take notations of the service beingrendered on these lines.

There subscribers lines such as B shown in the upper part of Fig. 1, areserved by line switches, the extension of the lines through the main andintermediate frames is substantially t-he same although the method ofconnecting the line to the observing position differs somewhat. Forexample, the connection is made at the intermediate distributing frameby means of the cords which terminate in plugs 112, 113 and 114i. Thelast two cords are attached as illustrated to the proper connectingpoints on the intermediate distributing frame by shoe 116, while thecord terminating in plug 112 is attached to one terminal of the linerelay 118 by a suitable attachment clip. The

Wil. llittltit same is true of lines which terminate in individualswitches, namely, that any desired number thereof may be connected tothe observing position at a time.

The equipment at the operators desk includes a talking set comprising areceiver 200 (F ig. 2) and a transmitter 229 and a plug and jack switch201 for rendering the equipment effective. By means. of his talking setthe operator may converse with a calling subscriber whose line has beencon* nected to his position. Furthermore, there are provided two cyclecounters 213 and 225. These devices may consist of any well knownmechanism responding to an alternating current and which serves to drivea counting member through one step for each cycle through which thecurrent passes. For operating the cycle counters, there is provided adriving fork 215 which may be adjusted to operate at any desiredfrequency. The frequency of the driving fork will determine by means ofan induction coil 214, the trequency set up in the secondary circuit,and consequently the frequency of the current flowing through the cyclecounters. ln an obvious manner the distance through which the movableelement of' the cycle counter moves in response to a current oi knownfrequency may indicate the exactamount of time elapsing trom the instantthe counter is started in operation until the operation ceases. Theprinciple of such devices is an old and Well known one for obtaining anaccurate measurement of time. The cycle counter per se is not concernedparticularly with the present invention and, therefore, it is notconsidered necessary to describe its operation and mechanism in det-ail.lt is merely one device for obtaining an accurate measurement of thetime required for certain operations in the system to take place. Anyother time measuring device might be used equally as well provided itgave the required degree oif accuracy. rlhe cycle counter 213, as willbe hereinafter described, is used for counting the time elapsing fromthe instant the subscriber initiates a call until a sender is attachedto his line ready to receive impulses. 'lhe cycle counter 225 is usedfor counting the time between the initiation of the call and the instantwhen the lirst impulse is sent from the substation.

In addition, the operators desk is equipped with a pen registermechanism consisting of a magnet 203, the armature oi: which carries apen arranged to engage a moving tape 230 to record the nature of theimpulses sent out over the calling line.

Certain other devices, to be described hereinater, are also located atthe operators position for making observations ot message registrationand coin operations.

The system in general and the appa atns involved therein having beenoutlined above,

a description will now be given of the detailed operation: 'To this endit is assumed at first that the observing operator wishes to inspect theservice beingvrendered on a certain group ot subscribers lines served byline finder switches. To do this, the operator connects each line ashereinbeit'ore eX- plained, to the connecting circuit leading to theobserving desk by means of the plug ended connecting cords. Since theidentity of each of the several connecting circuits is known, theidentity ot the lines to which they are made individual, respectively,is also readily determined.

After having connected up a group of lines on which the service is to beinspected, the observing operator renders his equipment effective forassociation with any line in the group that calls by completing the plugand jack connection 201. The insertion of these plugs in the jacksextends the conductor 204 over the spring contacts 203 to conductor 231.The conductor 231 leads through the upper contact of relay 232 to groundthrough the left normal contact of release key 209. The conductor 204ente-nds over parallel paths to the armature of each of the severalrelays 300, only one of which is shown. There is a relay 300 individualto each connecting circuit, and consequently, individual to theparticular subscribers line associated with the operators position bymeans ol such connecting circuit. rlhe relay 300 corresponds to the linerelay and energizes at the same instant the line relay is operated.lllhenever one of these relays operates, it connects the commonconductor 204 through its armature and contact to the winding of anindividual relay such as relays 302 and 303 as will presently bedescribed. lilith the apparatus thus in condition to make observations,it is now assumed that the subscriber of line A initiates a call.

Upon removing his receiver from the switchhook, the subscriber of line Acloses a circuit from battery through the winding of line relay 152,inner left contact of relay 151, through the intermediate and maindistributing frames, conductor 146, over the loop of the subscribersline and returning by way of conductor 145, through the main andintermediate distributing trames to ground at the right contact ot relay151. The line relay 152 becomes energized in this circuit and in thewell known manner causes the line iinder 132 to start in operation,searching tor the subscribers line. The line finder 132 may also be of'the panel power driven type provided with a plurality of sets of brushesarranged to be tripped when operated in the manner described in thepatent to J. L. McQuarrie No. 1,177 ,044, patented March 28, 1916. Acircuit is also closed at this time in parallel with relay 152 extendingfrom ground at the right armature contact of relay 151 over the circuitabove traced to conductor 146, thence over the distributing frames,conductor 148, sleeve of plug 123, sleeve of jack 120, conductor 103,strap 331, armature and back contact of relay 304, strap 332 to batterythrough the winding of relay 30.0.

At the same instant relay 152 energizes, the relay 300, also included inparallel therewith, attracts its armature. The relay 300 extends thecommon conductor 204 through its armature and contact, lett contact ofrelay 305, right winding .of relay 302, makebefore-break contact at theleft armature of relay 306, winding of relay 307 to battery. Theindividual relay 302 and the common relay 307 become operated in thiscircuit. Relay 302 closes a holding circuit for itself traceable frombattery through the left winding and inner left front contact of saidrelay, winding of relay 306, conductor 210, right Contact of key 209, toground. Relay 306 energizes in series with the locking circuit of relay302 and opens the origina-l energizing circuit of relay 302 whichincluded the winding of relay 307. Relay 307, however, remains energizedin a circuit from battery through its winding, the make-before-breakcontact at the left armature of relay 306, thence to ground overconductor 210. Relay 302 closes a circuit from battery through thewinding of relay 305, inner left front contact of relay 302 and thenceto ground over the conductor 210 as previously traced. Relay 305operates and creates a second break point in the Ioriginal energizingcircuit of relay 302. In parallel to the relay 305, relay 302 completesa circuit or the lamp 301 which is individual to the connecting circuit,and consequently, individual to the calling line A. The lamp 301illuminates and advises the operator that a call has been initiated onthis particular line.

The relay 302, furthermore, extends the circuit 308-309 leading from theoperators talking set by way of conductors 102 and 103 through to thesubscribers line conductors 145 and 146. In other words, theenergization of relay 302 causes the eXtension of the line A to theobserving operators telephone equipment, whereby conversation may beheld between the subscriber and the operator.

lith relays 300 and 302 operated a circuit is closed from ground, overconductor 204, Contact of relay 300, conductor 310 .outer left contactof relay 302, conductors 311 and 327, left back contact of relay 328,winding of relay 329 to battery. Relay 329 operates and completes acircuit from battery through its winding and the winding of relay 328 inseries, right contact oi relay I 329 to ground by way of conductor 210.

Relay 328, however, cannot energize since it is shunted out by thedirect circuit to ground traced through the contacts of relays 300 and302. Relay 329 also cl-oses a lcircuit from ground on conductor 210 overthe left armature contact of relay 329, the right armature and backcontact of relay 317 to battery through the middle polarizing winding ofpulsing relay 242, preparing this relay for later response to dialpulses, by throwing the armature of this relay against its back contact.

The observing equipment at the operators equipment is now connected tothe subscribers line A, which connection has taken place instantly inresponse to the initiation of al call on said line. Should another linein the group associated with the operators position by means of the plugand jack connections originate a call at any time during the connectionof the position with the line A, provision is made whereby said secondline will be inetlective to cause the connection of the operatorsposition thereto.

`This end is accomplished by rendering all remaining relays 303, etc.,which are individual to the other lines in the group inoperative inresponse to the energization of their corresponding relays 300. F rominspection of the drawing, it will be seen that the energizing circuitthrough the right winding of the relay 302 extends from battery throughthe winding of relay 307 and over the make-before-break contact of relay306. The conductor 330 leading from the contact vof relay 306 ismultipled to the operating winding of all relays 302, 303, etc. Sincethe relay 302 is energized and the common relay 306 is also operated,the conductor 330 is `opened at the make-beore-break contact of the saidlatter relay and, hence, no other relay 303, etc., can have itsoperating circuit closed due to the initiation of a call on the line towhich it is individual.

At the instant the relay 307 attracts its armatures, circuits are closedfor supplying alternating current to the cycle counters 213 and 225 inorder that these devices may commence to count time from the initiationof the call. rlhe circuit for counter 213 may be traced from batterythrough the tip of jack 211, tip of plug 212, thence through the counter213, slee-ve of plug 212 sleeve of jack 211, through the right windingsof coil 214, conductor 216, lowermost contact of relay 217, conductor218, outer contact of relay 307, inner right contact of relay 312,conductor 313, sleeve of jack 219, sleeve of plug 220, through thecounter 213 tip of plug 220, tip of jack 219, to ground. The circuit forapplying current to the othercounter 225 may be traced from batterythrough the tip of jack 223, tip of plug 224, through the counter 225i,sleeve of plug 224, sleeve of jack 223, thence through the rightwindings of coil 214, conductor 216, lowermost contact of relay 217,conductor 218, outer contact of relay 307, right contact of relay314,'co1iductor 315, sleeve of jack 227, sleeve of plug- 226, throughthe counter 225, tip of plug 226, tip of jack 227 to ground.

As soon as the line finder switch 132 advances its brushes onto theterminals tot the calling subscribers line A, the circuit yis completedin the usual well known manner -for the energization` of the cut-orfrelay151. This circuit leads from `a source of battery current `over theneXt to the lowest brush and contact of finder 132, through the windingof relay 151 to ground. A parallel circuit is also closed through theintermediate distributing traine to conducto-r 156, tip: of plug 124,tip of jack 121, conductor 106, through the winding ofrelay 304 toground.

It may be noted at this point that when the observing equipment visemployed for taking observations on lines which are served by lineiinder switches, the 'straps 331 and 332 are closed as indicated and areopened when observations are taken on lines which are served by lineswitches. These straps are ordinary manual devices adjusted by theoperator.

The cut-0E relay 151 opens the circuit of the line relay 152 and alsothe circuit of relay 300. Relay 304, upon energizing also opens thecircuit of relay 300. When relay 300 becomes deenergized, it opens theshunt around the winding of relay 328 and this relay operates in serieswith relay 329. Relay 328 closes a circuit for the illumination of lamp333, notifying the observer that the subscribers line has been found.

Then the subscribers line is extended to an idle register sender 135,the sender selector having chosen an idle sender in the manner set forthin the above mentioned patent to F. A. Stearn and F. J. Scudder, No.1,395,977, issued November 1, 1921, the imp-ulse relay of the selectedsender is co-nnected in circuit with the subscribers line in the usualmanner and relay 322 of the observing equipment is connected in acircuit therewith. This circuit leads from ground through the winding ofrelay 322, inner right armature and contact of relay 328, left armatureand contact of relay 323, conduct-or 309, inner right armature andcontact of relay 302, conductor 103, through the sleeves of jack 120 andplug 123, conductor 14S, terminals of intermediate frame through thenext to uppermost brush of the iinder 132, lower left contact of spring160 and thence to battery at the register sender 135. Relay 322 operatesin the circuit traced and completes a circuit from ground over conductor210, left armature and back contact of relay 314, contact of relay 322,back contact of relay 362, winding of relay 312 to battery. Relay 312yoperates and completes a circuit from battery through its winding andthe winding of relay 362 y in series, left contact of relay 312,conductor 363,1e2t't' normal ',contactof key `209, to ground. Relay 362,however, cannot operate in this circuit since `it shunted :by thecircuit closed through the contactjof relay 314. Relay 312 upon'attraetiijigl its armatures. opens the circuit previouslytraced"overconductor 313 for thev liow ot-jcurrent through vthe cycle counter 21,3.The cycle counter 2,13 thereupon ceases its operation, havingV measuredthetiine elapsing between the initiation of the fcalll on thesubscribers line, and the instant when an'idleregister sender 135becomes `attached to such. line ready to receive impulses transmittedfrom the lsubscribers dial. The'readifngfrom this counter may be takenat any desiredtime lby the observer. Relay 3112 also closes a4circuitfroin battery through the windingV of; relay 335, outer rig-htcontact `of relay 312 to ground over conductor 210 for aV purpose to belater described.

Immediately thatA the relay 312 operates, which occurs soonl after theextension of the subscribers line to the register sender, a circuit isclosed from battery `through the right winding of relay 323, outer rightcontact of relay 312 to ground over conductor 210. Relay 323 operatesanddisconnects the relay 322 from the conductor 309 to prevent thereenergization of said latter relay. Relay 312 also closes acircuitfrombattery through theA lamp 334, outer right contact of relay 312 to thegrounded conductor 210. The lamp 334 advises the operator that an idleregister sender has been seized.

Relay 312 also closes Ian obvious .circuit for 'rela-y' 317 in parallelwith` relay 335 and lamp 334. Relay 317 upon energizing o-pens at itsVright armature and back contact the previously traced polarizingcircuit for relay 242 and at its left armature contact establisheslalcircuit for relay 325. This latter circuit may be traced from batterythrough the winding of relay 325, left armature contact of relay 317,conductor 318, inner left armatureand back contact of relay 245,conductor 3119, left armature andback Contact of relay 314 toground onconductor 210. Relay 325 thereupon locks over its armature contact inseries with the Winding of relay 314 to ground 'on Vconductor 210. Relay314 being shunted, however, over the contactofrelay 245V dees notenergize atthis time. As scones relay 322 deenergizes, the shunt aroundthe winding of relay 362 is removed and relay'362 energizes in thelocking circuit of relay 312. Untilthe irst iinpulse isl dialled thearmature of relay 242 is held against-its back contact by a circuitextending from battery over the middle winding' ofi'relay 242, highresistance'elementV 250, the` arniat I' ef and back f contactA of relay242; thel rig'htariiiatuie' and front con llO tact of relay 317 thenceto ground on conductor 210.

It is assumed that the subscriber at substation A has allowed asuificient time for the apparatus at the central oiiice to associate asender with his line following the initiation of the call. He thenmanipulates his dial to transmit the first series of impulsescorresponding to the wanted designation. Upon the first opening of theline by the impulse sender, a surge of current passes over an inductivebranch of the pulsing circuit extending from conductor 148, sleeves ofplug 123 and ack 120, conductor 103, inner right armature and contact ofrelay 302, conductor 309, condenser 252, left winding of polarizedpulsing relay 242, right winding of repeating coil 253, conductor 308,outer right armature and contact of relay 302, conductor 102, tips ofjack 120 and plug 123 to conductor 147. This surge of current causesrelay 242 to attract its armature against its front contract, openingthe circuit through its middle winding and closing a circuit extendingfrom battery sleeves of jack 206 and plug 207 pen register magnetwinding 208, tips of plug 207 and jack 206, winding of relay 245,armature and contact of relay 242, conductor 254, armature and contactof relay 317 to ground on conductor 210. A circuit is also establishedfrom ground on conductor 254 through the armature and front contact ofrelay 242, right winding of this relay, high resistance element 251,right armature and back contact of relay 243 to battery. -The currentnow flowing through the right winding of relay 242 locks the armatureyagainst its front Contact.

On the next closui'e of the subscribers line circuit current surgesthrough the left winding of polarized relay 242 in the reverse directionthrowing the armature thereof against its back contact in which positionit is held by current flowing through the middle winding of the relay aspreviously described. This action of relay 242 is thus repeated for eachimpulse dialled by the calling subscriber, the magnet 208 energizingeach time rela-y 242 attracts its armature against its front contact,and deenergizing each timeJ relay 242 throws its armature against itsback contact. Thus the magnet 208 is energized for aI periodcorresponding to the duration of each line opening and records on therecording t-ape 230 such period by a pen attached to its armature. Arecord is thus made of each impulse dialled. Relay 245 which operates inseries with magnet 208 upon its first energization, opens the circuitpreviously traced over conductors 318 and 319, thereby removing theshunt from around the winding of relay 314. Relay 314 thereupon operatesin series with relay 325 and locks to ground over the conductor 210. Therelay 314 at its right armature opens the circuit over conductor 315 forsupplying current to the second cycle counter 225. This counterthereupon ceases to operate having accurately measured the time elapsingbetween the initiation of the call and the instant when the firstimpulse was transmitted by the subscriber.

Following the last impulse dialled by the subscriber the line loopbecomes closed and remains closed during conversation, and relay 242operates to hold its armature against its back contact. When thesubscriber hangs up to release the connection the line loop is againopened and relay 242 operates to move its armature against its frontcontact. The pen register magnet is again operated and would be heldoperated until the operator released the connection thus needlesslywasting recording tape unless some provision were made to force thearmature of relay 242 against its back contact after an interval longerthan would ordinarily measure the duration of a regular dial pulse. Thisis accomplished by a chain of slow operating relays 246, 244 and 243which operate in succession, relay 243 upon operating opening thecircuit through the right holding winding of relay 242 and closing acircuit at the left contact of relay 243 from ground on conductor 254,through resistance 250 to battery through the middle winding of relay242. The current flowing through the middle winding of relay 242 forcesthe armature of this relay against its back contact. The circuits foroperating relays 246, 244 and 243 upon a continued energization of relay245 and magnet 208 are obvious and need not be traced herein.

Assume that the calling line is one on which a coin box is located. Inthis case coin collect or refund current will be applied to the line atsome time during the release of the connection in thc usual manner. Itis desirable that the observing operator be notified with respect to theoperation of the coin box both as regards the character of the currentapplied and also the time and duration thereof. For this purpose, thelamps 235 and 236 are provided, one of which signifies that coin collectcurrent is being applied to the line, while the other signifies` thatrefund current is being sent over the line. Tf the call succeeds, asource of collecting current is applied and in addition to flowing' overthe subscribers line, it also flows over the tip conductor' through theintermediate distributing frame, thence as heretofore traced over theconductor 102, outer right contact of relay 302, conductor 308, windingof relay 237, windings of polarized rela-y 238, to ground. Relay 237operates, but the polarity of the current is such that thepolarizedrelay 238 remains inert. Consequently, a circuit is closed frombattery through the winding of relay 239, lamp 236, back contact ofrelay 233, to ground at the front contact` of relay 237. The lamp 236notities the operator that collecting currentis being applied to thesubscribers line. In order that the observers attention may be attractedat this time, the relay 239, on energizing, completes a circuit 'for thebuzzer 240. If on the other hand, refund current is applied, itspolarity being or' an opposite character, both relays 237 and 233 areoperated. In this event, a circuit is closed from battery lthrough thewinding of` relay 239, lamp 235, trent contacts ot' relays 233 and 237to ground, causing the illumination of the lamp 235.

Should the calling subscribers line A be one which is equipped with amessage register, it is also desirable that the observer be aware of thefact that the register is operated properly. Atthe time ofdisconnection, ifthe call proved to be successful, a message registersource of current is applied in the usual manner over the lowerrnostbrush of the finder switch 132, Contact of the line relay 152, through`the intermediate distributing frame, thence over two parallel branches,one of which leads through the winding of message register 153, backthrough the. distributing trame, through the left ront contact of thecut-off relay 151 and to ground, and the other of which eX- tends overconductor 157, sleeve of plug 124, sleeve of jack 121, conductor 107,`right contact of relay 305, conductor 316, strap 205, through thewinding of relay 223 to ground. Relay 2,23 operates and closes a circuitfrom battery through the winding of relay 239, lamp 241, to ground atthe contact of relay 223. The lamp 241 and the buzzer 240 advise theobserver that the message register of Ctlhe calling line has beenproperly operate After having' completed his observations on thesubscribers line A, t-he operator may disconnect the equipment at hisdesk from said line, in order to render it connectable to some otherline in the group, by manipulat ing the release key 209. Upon operatingthe key 209, ground is removed trom the conductors 210 and 363 therebypermitting relays 302, 306, 307, 305, 323, 329, 362, 312, 317, 314, 325,335 and 323 to become deener gized. The release of these relays alsocauses the extinguishment of the lamps 301, 333 and 334.

While provision has been made through the circuits controlled by relays202 and 232 for preventing the association of the observing circuit witha second calling line if the operator depresses the release key 209torelease the circuit from a first line at a time when a call hasalready been initiated on such second line, the detailed operation ofsuch relays will not be described herein.

Reference to my Patent No. 1,504,230 hereinbefore referred to may be hadfor such description.

When it is desired to associate the equip ment with subscribers linesserved by line switches, the connections are made, as illustrated, inthe. upper part of Fig. 1. In addition to connecting the differentterminals on the intermediate distributing frame with the connectingcirc-uit to the operators position, it is necessary in this case to clipconductor 140 to the terminal of line relay 113.

Then the subscriber of line B initiatesa call a. circuit is closed inthe usual manner for the line relay 113 and may be traced from batterythrough the right hand winding of said relay, inner right armature andback contact of cut-off relay 142, thence over the line conductor 137,returning by way ot conductor 136, lett contact of relay 142, to ground.The line` relay 113 operates and initiates the movement of the lineswitch 123 in the usual manner. A circuit is also established inparallel with relay 113 extending over conductor 140, tips of plug 112and jack 103, conductor 104 to battery through the winding of relay 300.The stra-ps 331 and 332 are opened for observation of lines of the typeand relay 304 is also ineffective.

In response to the energization of relay 300, the same series ofoperations occur at the operators equipment as described in connectionwith the line A. Relay 302 is operated, and in turn, starts theenergiZat-ion of relays 306, 329, 305l and 307.

When the line switch 123 linds an idle trunk leading to a districtselector switch 130, the cut-off relay 142 is operated, therebydisconnecting the line relay 113 and also opening the circuit of relay300. In response to the deenergization of relay 300, the same operationsyoccur at the observers desk as previously explained. Relay 323 isoperated and lamp 333 illuminated, notifying the operator that adistrict switch has been selected. When subsequently, an idle registersender 131 is attached, the relay 322 becomes energized as hereinbetoredescribed, causing the actuation ot relay 312 and the stopping of thecycle counter 213. In response to the lirst impulse sent out by thecalling subscribers dial, relay 314 becomes operated and the secondcycle counter 225 is arrested. In parallel with the circuit of thecutoff relay 142 a branch leads from the terminal of the intermediatedistributing frame, thence over conductor 155, sleeve of plug 114 andjack 110, conductor 107, right contact of relay 305, conductor 316,strap 205, in engagement during the observation of a. line of thischaracter with its lowerinost contact, windings of relays 249 and 243,right armature and back contact of relay 247, to ground at the contactof relay 335.

Relay 243 operates in this circuit but relay 249 being' marginal doesnot operate at this time. Relay 248 upon energizing' closes a circuitfrom ground on conductor 363, through the armature and contact of relay248, the inne-r left armature and back contact of relay 247, the windingof relay 234, to battery through the left winding of relay 247., theresistance of relay 234 is such that relay 247 does not receivesuflicient current to operate at this time. Relay 234 upon energizingprepares a circuit for the lamp 241. Relay 234 at its right armaturealso prepares a circuit through the right winding of relay 247.

If the subscriber-s line has no message register or the 'call is notcharged, when the subscriber hangs up his receiver battery isdisconnected from the windings of cut-olf relay 142 and relays 248 and249. Relay 248 upon deenergizing removes the shunt from around the rightwinding of relay 247, so that relay 247 energizes in a circuit extendingfrom battery through its left winding, the winding of relay 234, theright winding of relay 247, the right armature of relay 234 to ground onconductor 363. Relay 247 at its right contact opens the circuitpreviously traced through the windings of relays 248 and 249 so that asthe subscribers line switch 128 restores, the lower brush thereof cannot|connect full battery potential encountered on the test terminals ofidle districts to the windings of relays 248 and 249. This prevents a`false operation of lamp 241 through the false operation of relay 249.Relays 234 and 247 are released as soon as the operator depressesrelease key 209.

If the subscribers line B is one provided with a message register,metering current is applied at a suitable time over a. circuit leadingthrough the lowermost brush of the line switch 128, thence through theintermediate distributing frame, winding of the message register magnet154, through the outer right contact and right winding of relay 142 toground. rlhis metering cur rent also flows over the circuit tracedthrough the windings of relays 248 and 249,l being' of suilicientstrength to operate marginal relay 249. The circuit of meter lamp 241 isnow completed from battery, winding of relay 239, lamp 241, left contactof relay 234 to ground at the armature end contact of relay 249. Uponthe release of the connection relays 248 and 249 deenergizc and relay247 energizes as before described. The energization of relay 247 inaddition to opening the circuit for relays 248 and 249 prepares acircuit for relay 233 extending from battery, winding of relay 233,outer left armature and contact of relay 247, conductor 255 to the`front contact of relay 362.

Should the subscriber on line B make a second call before the operatordepresses release key 209, relays 234, 247 and 362 will be at the timeenergized and when relay 300 energizes in response to a new call, thecircuit of relay 233 will be completed from the armature of relay 362,left armature and front contact of relay 328, conductors 327, and 311,outer left contact of relay 302, armature and contact of relay 300 toground on conductor 204. Relay 233 will thereupon energize shortcircuiting the winding of relay 234 causing its deenergization. Relay247 will be maintained energized through the armature and Icontact ofrelay 233. When relay 300 deenergizes following connection with an idledistrict, the circuit of relay 233 is opened and relay 233 deenergizesopening the circuit of relay 247. Relay 247 now restores the energizingcircuit of relays 249 and 248 so that these relays are in a position tode termine if the second call is properly registered.

All other operations are substantially the same as hereinbeforedescribed in detail in connection with the observation made on thesubscribers line A.

l/Vhen the observing equipment is used to make observations onsubscribers lines in a step-by-step switching system, the connection ofthe equipment may be made in substantially the same manner as shown inthe lower part of Fig. 1 by use of cord circuits which lead from themain distributing frame to the jacks provided for this purpose. Thecircuits and apparatus shown in Fig. 3 respond during the extension ofthe subscribers line in the step-by-step system upon the initiation of acall for controlling the observing devices at the position shown in Fig.2 in substantially the saine manner as already described in detail.Strap 375 is closed at this time so that relay 312 is operated to stopcycle counter 213 as soon as the time switch plunges and operates relay304.

In case of observations made on subscribers lines in a step-by-stepsystem, the cycle counter 213.would serve to measure the time from theinitiation of the call to the instant when the subscriber-s line hadbeen extended to a first selector switch ready to receive impulses. Thecycle counter 225 would be employed for taking a measurement of the timeelapsing between the initiation of the call and the instant when thesubscriber operates his dial. It will be obvious how the pen registermechanism, the message register signals and the other elementsassociated with the observers desk are operated to give the same recordsand indications for a subscribers line in a. stepby-step system as forthe lines A or B terminating in an office where power driven switchesare involved. In this case how- "lil,

extending connections from said line, im

pulse sending means associated -with said line for automaticallycontrolling said line extending means, an impulse relay, means forinductively associating said relay with said line, and a recordingdevice controlled by said relay for recording impulses transmitted bysaid impulse sending means.

3. In a telephone system, a line, switching devices, means :torextending a control circuit from said line to said devices, impulsesending means associated with said line for automatically controllingsaid switching devices, an impulse relay, means Jfor inductivelybridging said relay across said control circuit and a recording devicecontrolled by said relay for recording impulses transmitted over saidcontrol circuit from said impulse sending means.

ll. In a telephone system, a plurality ot lines, an operators position,means responsive to the initiation of a call on one of said lines forextending said line, means responsive to the initiation of said call forconnecting the operators position to said line, selector switches forfurther extending said line, impulse means associated with said linesJfor controlling said switches and means at said operators positionindulctively responsive to said impulse means for recording the impulsestransmitted thereby.

5. In a telephone system, a line, switching devices, means for extendinga control circuit rom said line to said devices, impulse sending meansassociated with said line for cont-rolling such switching devices, animpulse relay, means for inductively bridging said relay across saidcontrol circuit and a recording device controlled by said relay forrecording impulses transmitted over said control circuit from saidimpulse sending means, said relay operating to close the circuit of saidrecording device upon each opening ot said control circuit and to openthe circuit of said recording device upon each subsequent closure ofsaid control circuit.

6. In a telephone system, a line, switching devices, means for extendinga control circuit from said line to said device-s, impulse sending meansassociated with said line for controlling said switching devices, apolarized impulse relay, means for inductively bridging said relayacross said control circuit, a recording device controlled by said relayfor recording impulses transmitted over said control circuit from saidimpulse sending means, said relay operating to close the circuitof saidreco-rding device upon each opening of said control circuit and to openthe circuit of said recording device upon each. subsequent closure otsaid control circuit, and locking winding for said relay for holding thearmature thereof in either its front or back positions.

7 In a telephone system, a plurality of linesyan operators position,means responsive to the initiation of a call on one of said lines forextending such line, means responsive to the initiation of said call forconnecting the operators position to said line, selector switches i'orfurther extending said line, impulse means lassociated with said ,linefor controlling said switches, a polarized impulse relay, means forinductively associating one winding of said relay with said calling lineover said connecting means, a

recording device controlled at a front contact ot said relay forrecording impulses transmitted by said impulse means, and a polarizingcircuit :tor said relay closed upon the initial connection of `saidoperators position with said line for positioning'the armature ot saidrelay against its .back contact.

8. In a telephone system, a plurality of lines, an operators position,means responsive to the initiation ot a call on one of said lines forextending such. line, means responsive to the initiation ot said callfor connecting the operators position to said line, selector switchesfor further extending said line, impulse means associated with said linefor controlling said switches, a polarized impulse relay, means vforinductively associating the operating` winding oi' said relay with saidcalling line over said connecting means, a recording device controlledat a front contact of said relay for recording impulses transmitted bysaid impulse means, and two polarizing windings for said relay forholding' the armature thereof in either ot the contact-ing positionsinto which. it is moved by said operating winding.

9. In a telephone system, a plurality ot lines, an operators position,means responsive to the initiation of a call on` one of said lines forlextending' such line, means responsive to the initiation of said call:tor connecting the ofperators position to said line, selector switchesfor further extending said line, impulse means associated with said linefor controlling said switches, a polarized impulse relay, means forinductively associating said relay with said calling line over saidconnecting means, a recording device controlled at a front Contact ofsaid relay for recording impulses transmitted by said impulse means, apolarizing winding for said relay, and time controlled means for closinga circuit through said polarizing winding to open the circuit of saidrecording device in case said impulse relay fails to function to thatend under the control of the calling line within a predetermined period.

l0. In a telephone system, a line, switching devices, means forextending a control circuit from said line to said devices, impulsesending means associated with said line for contro-lling said devices, apolarized impulse relay, means Jfor inductively bridging said relayacross said control circuit, a recording device for recording impulsestransmitted over. said control circuit from said impulse sending means,said relay operating to close the circuit of said recording device uponthe opening of said control circuit and to open the circuit of saidrecording device upon the subsequent closure of said control circuit, apolarizing winding 'for said relay, and time controlled means forclosing a circuit ythrough said polarizing winding to open the circuitof said recording device in case said control circuit remains open forlonger than a predetermined period.

l1. In a telephone system, a plurality of lines, an loperators position,means responsive to the initiation of a call on one of said lines forextending said line, means responsive to the initiation of said call forconnecting the operators position to said line, electromagnetic meansindividual to each of said lines, a. circuit extending through said lineextending means for operating said electromagnetic means, a signal atsaid operators position for indicating the operation of saidelectromagnetic means, and means for preventing a false operation oisaid signal during the restoration of said line extending means.

12. In a telephone system, a plurality of lines, an operators position,means responsive to the initiation of a call on one of said lines forextending such line, means responsive to the initiation of said call forconnecting the operators position to said line, electromagnetic meansindividual to each of said lines, a circuit extending through said lineextending means and eiective for operating said electromagnetic meansfollowing the restoration of the calling subscribers receiver to theswitchhook for releasing the extended connection, a signal at theoperators position for indica-ting the operation of said electromagneticmeans, and means for preventing a false operation of said signal duringthe restora. tion of said line extending means.

In witness whereof I hereunto subscribe my name this 7th day of July, A.D., 1923.

JOI-IN W. GOODERHAM.

